MY NEW IDEAS 403 



I am now inclined to think that it accounts for more of the 

 variety and beauty in the animal world than any other purpose 

 yet discovered. 1 



I may here add that I believe I was first to give adequate 

 reasons for the rejection of Darwin's theory of brilliant male 

 coloration or marking being due to female choice. 



6. The general permanence of oceanic and continental 

 areas was first taught by Professor J. D. Dana, the eminent 

 American geologist, and again by Darwin in his " Origin of 

 Species" ; but I am, I believe, the only writer who has brought 

 forward a number of other considerations, geographical and 

 physical, which, with those of previous writers, establish the 

 proposition on almost incontrovertible grounds. My exposi- 

 tion of the subject is given in " Island Life' (chap, vi.), 

 while some additional arguments are given in my " Studies ' 

 (vol. i. chap. ii.). The doctrine may be considered as the 

 only solid basis for any general study of the geographical 

 distribution of animals, and it is for this reason that I have 

 made it the subject of my careful consideration. 



7. In discussing the causes of glacial epochs I have adopted 

 the general views of Mr. James Croll as to the astronomical 

 causes, but have combined them with geographical changes, 

 and have shown how the latter, even though small in 

 amount, might produce very important results. In particular 

 I have laid stress on the properties of air and water in 

 equalizing temperature over the earth, while snow and ice by 



1 A correspondent, Mr. G. Norman Douglass, writing from the British 

 Embassy, St. Petersburg, in 1894, sent me the following translation of a 

 passage in Schopenhauer's " Die Welt als Wille und Vorstellung (Zur 

 Teleologie)" which curiously anticipates my views: — 



" One accounts for the wonderfully varied and vividly glowing color- 

 ation of the plumage of tropical birds, although only in a very general 

 way, by the stronger influence of light between the tropics — as its causa 

 eMciens. As its causa finalis, I should say that these brilliant plumages 

 are the full-dress uniforms by means of which the individuals of the 

 numberless species, often belonging to one and the same genus, recog- 

 nize each other, so that every male finds its female." 



